Researches
Players can upgrade most things they control in the game through the Researches interface. Standard research becomes available after unlocking level 2.1. A limited branch of research (using green papers and stars earned in levels to purchase) is available from the beginning. Research costs Green Papers, Resources, and occasionally time, level "stars", or other researches having completed. Most researches have a number of levels, each of which will be more expensive and cost more advanced resources than the previous level. The border around the research will indicate: * Purple - Can afford to purchase the next level * Grey - Cannot afford the next level, and currently level 0 * Green - Cannot afford the next level, currently above level 0 * Gold - Maximum level purchased already Research Screen (format changed after more recent game updates, but the basic interface is the same) 1: Current resources Shows what current resources you have to spend: # Unopened items. Click here to open them. This is items you have earned in levels, or Boxes you have purchased, but not yet opened # Number of Accelerators. These are earned from defeating certain enemies within levels, finishing certain quests, or opening purple/orange boxes. They are used to complete timed researches early, upgrade custom map tiles, and to replenish Mining energy. # Amount of each Resource ( , , , or ) you own. Only resources you have already unlocked in research are shown here. These are earned from mining source tiles, completing quests or opening boxes. They are used to do research or purchase Abilities. # Green Papers. Click here to access the Shop. These are earned by completing levels or quests. They are used to purchase upgrades or boxes from the shop. 2: Research Effects Shows what the selected research is currently doing (if applicable) and how that will change if another level is purchased. 3: Research Requirements The cost of buying the next level of the research. This can include: * Previous research having been completed. In some cases there is a small number shown on the line (eg "6/7"). This means that the linked research must have been researched up to the specified level to unlock this one. * Other requirements. In some cases specified things need to have happened to purchase this research. For instance in the picture, 1 million damage must have been dealt using the sniper tower. * Resources cost. The quantity of , , , , or Bit Dust required. * Green Paper cost. * Stars cost (upgrades on the left side of the research tree) * Research levels completed (total amount of research player unlocked (eg "2.18K/2.25K"). This is the requirement for the Developer mode. 4: Research Time If applicable, will show the number of minutes (First generation upgrade is 5 minutes, second is 15 minutes and third is 30 minutes) that doing this research will take. Research that that require time locks the entire research tree until it has finished. The wait can be removed by spending Accelerators after the research has started. 5: General Research Section This section allows research into: * Unlock new resource types, Miners, and miner upgrades ** is unlocked with the first upgrade ** is unlocked with the 4th upgrade ** is unlocked with the 7th upgrade ** is unlocked with the 13th upgrade ** is unlocked with the 18th upgrade ** Bit Dust becomes available as a reward in Endless mode. * Unlock and upgrade Abilities * Unlock new levels * Unlock map editor for Custom maps with the 10th upgrade * Unlock and upgrade Modifiers 6: Global Upgrade Section This section allows research into: * Global Tower upgrades, eg projectile speed and damage. These apply to every tower built. * Global game upgrades, eg starting money and health and increased green paper earning. * Global Miner upgrade, reducing deployment time. 7: Specified Tower Sections Each unlocked tower has it's own section allowing upgrades to that tower to: * Increase each common and unique characteristics * Increase the maximum XP and upgrade levels * Increase XP generation * Reduce purchase cost * Increase starting XP level * Increase the tower generation. These are expensive upgrades that also cost time, and require that you have have dealt a certain amount of damage with the tower. They award a significant increase the specified characteristics. zh-tw:研究 ru:Исследования